1. Field of the Invention
The present invention relates to a machine tool with a working area closed by walls and a roof covering, in which working area a device for receiving a work piece and a headstock with a main spindle are arranged, into which main spindle tools for machining the work piece can be clamped, whereby the device and the headstock are movable relatively to each other, and whereby in a front wall an opening to be closed by a door leads into the working area.
2. Related Prior Art
Such machine tools are known from the prior art.
In known machine tools, a housing is provided, which completely surrounds the working area and the headstock, the housing being further divided by inner walls, so that the working area is closed towards the guide rails and other equipments of the machine tool. This closed working area ensures that chips arising from machining the work pieces and used coolant do not result in contamination of the ambient and e.g. of the guideways, which would be disadvantageous for obvious reasons. In the working area, a device for receiving the work pieces to be machined is provided, whereby, further, the headstock projects, at least with its spindle head carrying the main spindle, into the working area, so that the tools clamped in the main spindle can be used for machining the work piece.
For the exchange of the work piece, the door provided in the front wall of the housing is opened, whereupon the work piece is first of all sprayed off/rinsed off by means of compressed air or a cleaning liquid, before it is then taken off. After that, the device is cleaned by means of compressed air or cleaning liquid, before a new work piece is clamped into the device, the door is closed and the machining is continued.
In such machine tools, it is further known to divide the working area into a loading side and a machining side, and to provide a partition wall between the loading side and the machining side in such a way that, during the machining of a work piece on one side, a readily machineed work piece can be exchanged against a new work piece to be machineed on the other side. The loading side and the machining side can be, in this procedure, exchanged in the rhythm of the work piece machining.
It is known for machine tools with closed working area to configure the rear wall of the working area by a bellow, which is fixed with its one end at a side wall of the housing and with its other end at the headstock. In this way, the bellow is shortened or lengthened in x-direction. Usually, on both sides of the headstock, there are two bellows, which, correspondingly, lengthen and/or shorten in opposite direction, if the headstock is moved in x-direction.
It is also known to configure the roof covering by such bellows, which are arranged between the respective side wall and the assigned side of the headstock. It is further known to arrange a bellow extending in y-direction between the face of the headstock and the front wall of the housing, whereby this bellow is lengthened or shortened in y-direction, if the headstock is moved.
All these machine tools have the disadvantage that only devices and work pieces with certain dimensions can be loaded and discharged through the opening provided in the front wall, a crane loading of very bulky and/or very heavy work pieces and/or devices is only possible by using a U-shaped fork laterally engaging through the opening into the working area. Such a loading is, however, disadvantageous both of static reasons and of handling reasons.
To remedy this problem, it is already known for fully enclosed machine tools to extend the door in the front side of the housing to the top and to extend the door to the rear over the roof area, so that a door is created, which is angle-shaped in the cross section, and, when being moved, releases a loading opening, which releases the working area both to the front and to the top. For such a door with a xe2x80x9croof sectionxe2x80x9d, consequently, also a crane loading from the top is possible.
Such machine tools have the disadvantage, however, that the door is very heavy and very large, so that it is large-scale in design, and the guidings have to be configured correspondingly. This results not only in very expensive and awkward designs, the whole construction height of the machine tool is, moreover, very large, as the door has to extend up to over the height of the headstock. A further disadvantage in such machine tools is that such a large door is only with high effort configurable in such a way that it provides, in a closed state, for a safe sealing of the working area to the outside.
A further disadvantage in such machine tools is to be seen in the fact that heat accumulation arises in the working area. The heat arising from the operation of the motors, e.g. for the moving of the headstock or the drive of the main spindle, heats up the working area and, thus, influences negatively the thermal stability of the machine tool.
In view of the above, it is an object of the present invention to allow a simple loading from the top of the known machine tool in a design constructively as simple as possible, by reducing the disadvantages from the prior art.
In the machine tool mentioned at the outset, this object is essentially achieved, according to the invention, in that at least a part of the roof covering is movable between two positions in such a way that it closes the working area to the top in a first position, and in a second position opens the working area to the top for loading.
In this way, it is now possible, additionally to the opening lockable by the door, to alternatively release a large loading opening, which is accessible from the top and through which a crane loading of even largest and heaviest parts is possible. The inventors of the present invention have namely recognized that not an enlargement of the door provided in the front section and its extending into the roof section results in a better loading capacity, but, rather, a roof covering to be opened independent of the door can be reached with constructively simple measures. The roof covering can, in this procedure, be upward folded, be moved to the front or to the rear and/or to the side, or it may be rolled up, so that, to the top, a loading opening arises, which can be considerably larger than the opening lockable by the door in the front wall. In other words, even if the machine tool is configured for machining very bulky and/or heavy work pieces, there is not an extremely large door necessary, the accessibility is, rather, made possible by the removable part of the roof covering.
It is then preferred if the roof covering comprises at least one bellow, which is movable both with and separated from the headstock.
In this measure, it is advantageous that the opening and the locking of the roof covering is performed in a constructively simple way, namely by moving a bellow. Another object is in this design that the machine tool in its entirety can be constructed with a lower height, since the bellow forming the roof covering can be fastened laterally at the headstock or near to same in such a way that it protrudes partly to the top over the bellow, a housing reaching over the headstock is not necessary.
It is further preferred in this connection if a console is provided, which is movable to-and-fro between the headstock and a first side wall, and that the at least one bellow of the roof covering extends between the console and the headstock, wherein preferably on both sides of the headstock, a console with corresponding bellow as roof covering is provided.
This measure is in particular constructively advantageous, by a simple moving of the console, the working area is opened to the top on the corresponding side of the headstock. If two such consoles exist, the machining side and the loading side can be loaded alternately.
It is here generally preferred if the roof covering comprises a further bellow, which extends between the headstock and the front wall, and which is movable both with and separated from the headstock.
Thus, it is a further object of the invention that the loading opening accessible from above is enlarged in a constructively simple way. This is achieved since the loading opening is here, so-to-speak, enlarged by the regions in front of the headstock, which are covered by the other bellow.
It is further preferred if between the console and the assigned side wall, a first rear bellow, and between console and headstock, a second rear bellow are arranged.
In this measure, it is advantageous that, independently of the position of the console, the working area is always closed to the rear, so that the guidings and aggregates being arranged there are protected against contamination. If during the loading process the console was accordingly moved towards the headstockxe2x80x94maximally, however, only up to the size of the working field to be loaded by cranexe2x80x94, so that the working area is open to the top, the first rear bellow closes the working area to the rear, so that no chips can arrive on the guidings or enter the protected aggregates, when the device is blown off.
During the machining of a work piece, the console is moved outwardly, so that the upper bellow and the second bellow, together with the side wall and the front wall, provide for a sealing of the working area.
It is true that it would also be possible to arrange a bellow each to both sides between the side wall and the headstock and to move the console independently of the respective rear bellow, in this way, however, sealing problems would occur in the area of the contact point between the upper bellow of the roof covering and the rear bellow.
The inventors of the present invention have recognized that, in spite of the at first glance disadvantageous arrangement of two rear bellows, there is yet a great advantage in this design, which is namely the better sealing of the working area in the region of the contact point between the roof covering and the rear wall. If, namely, only one rear bellow was provided, an additional guiding would have to be provided in the region of the contact point, in which, on the one hand, the rear bellow and, on the other hand, the bellow of the roof covering runs, as these are movable independently of each other.
In the selected design with two bellows, however, a better sealing can be provided, whereby it is particularly preferred if the second rear bellow and the assigned bellow are firmly connected with each other, preferably integrally configured with each other.
In this way, a good sealing in the contact area is provided.
It is also generally preferred if the console has a frame with a drive of its own, which frame is guided on guidings behind the working area, whereby the drive preferably comprises a pneumatic cylinder, which further preferably comprises a pneumatic cylinder without piston rods but with a magnetic coupling between the piston and the displaceable outer tube.
In this measure, it is advantageous that a very elegant drive for the console can be realized, which has, essentially, the same dimensions in x-direction as the console is movable, so that hereby the overall width of the new machine tool is not changed.
Further, it is also preferred if the opening in the front wall extends to the top up to the movable part of the roof covering.
In this measure, it is advantageous that the loading opening is accessible on nearly the whole width of the machine tool from the top as well as on the width of the door also from the front, whereby the opening in the front wall and the loading opening overlap each other, so that larger work pieces can also be brought obliquely from the front into the working area.
If the machine tool is configured for alternating machining of work pieces on the machining side and on the loading side, two doors, of course, must be provided, which are alternatively opened either manually or automatically.
Finally, it shall be mentioned that the design with the opening roof covering can also be used when the relative movement between the headstock and the device is performed in that way that a work piece table receiving the device is moved.
Further advantages can be taken from the description and the enclosed drawings.
It is to be understood that the features mentioned above and those yet to be explained below can be used not only in the respective combinations indicated, but also in other combinations or in isolation, without leaving the scope of the present invention.